Even before the life of Prophet Muhammad (Peace Be Upon Him) in the 600s, Arab traders were in contact with India. Merchants would regularly sail to the west coast of India to trade goods such as spices, gold, and African goods. Naturally, when the Arabs began to convert to Islam, they carried their new religion to the shores of India. The first mosque of India, the Cheraman Juma Masjid, was built in 629 (during the life of Prophet Muhammad) in Kerala, by the first Muslim from India, Cheraman Perumal Bhaskara Ravi Varma. Through continued trade between Arab Muslims and Indians, Islam continued to spread in coastal Indian cities and towns, both through immigration and conversion.

Muhammad bin Qasim

The first great expansion of Islam into India came during the Umayyad Dynasty of caliphs, who were based in Damascus. In 711, the Umayyads appointed a young 17 year old man from Ta'if to extend Umayyad control into Sindh: Muhammad bin Qasim. Sindh is the land around the Indus River in the Northwestern part of the subcontinent, in present-day Pakistan. Muhammad bin Qasim led his army of 6,000 soldiers to the far eastern reaches of Persia, Makran.

He encountered little resistance as he made his way into India. When he reached the city of Nerun, on the banks of the Indus River, he was welcomed into the city by the Buddhist monks that controlled it. Most cities along the Indus thus voluntarily came under Muslim control, with no fighting. In some cases, oppressed Buddhist minorities reached out to the Muslim armies for protection against Hindu governors.

Despite the support and approval of much of the population, the Raja of Sindh, Dahir, opposed the Muslim expansion and mobilized his army against Muhammad bin Qasim. In 712, the two armies met, with a decisive victory for the Muslims. With the victory, all of Sindh came under Muslim control.

It is important to note, however, that the population of Sindh was not forced to convert to Islam at all. In fact, for almost everyone, there was no change in day-to-day life. Muhammad bin Qasim promised security and religious freedom to all Hindus and Buddhists under his control. For example, the Brahman caste continued their jobs as tax collectors and Buddhists monks continued to maintain their monastaries. Due to his religious tolerance and justice, many cities regularly greeted him and his armies with people dancing and music.